Handheld portable modem



FIG. 1 is a top, right and front perspective view of a handheld portable modem showing our new design;

FIG. 2 is a rear elevational view;

FIG. 3 is a left side elevational view; and,

FIG. 4 is a bottom plan view.

The broken line matter shown in FIGS. 1, 3 and 4 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a handheld portable modem, as shown and described. 